The present invention relates generally to the fabrication and laser deletion of microfuses and more particularly to a process for fabricating a microfuse within an integrated circuit and deleting such microfuse by one or more laser pulses.
The use of microfuses in digital integrated circuits is well known for the purpose of selectively disconnecting unwanted components from the circuit. A known technique for deleting such fuses from the circuit involves the application of a laser light beam to the microfuse fuse link having sufficient energy to melt the fuse link. Such a technique has traditionally involved reducing or removing any passivation oxide present over the fuse link structure, thereby creating a window to facilitate the deletion of the fuse. During the fuse-deletion process, a crater is typically formed exposing the remains of the disintegrated fuse to the surrounding area. This process has the potential to cause many adverse effects to the portion of the integrated circuit in proximity to the deleted fuse, such as delamination of the circuit, contamination of the circuit with deleted particles, and corrosion. In addition, it has been difficult to obtain a satisfactory yield of deleted fuses using such prior techniques.